<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<meta>

<!-- <meta name="viewport" content="width=device-width, initial-scale=1.0"> -->
<title></title>
<style type="text/css">


/* html{ font-size: 62.5%;} */
/* body {
    background-color: yellow;
    font-size: 1.5rem;
} */



/* .box{
    background-color: aqua;
    width: 50rem;
    height: 50rem;
}
span{
    font-size: 5rem;
} */

.box{
    background-color: aqua;
    width: 10vw;
    height: 10vh;
}
span{
    font-size: 1vh;
}
</style>
</head>
<body>

<div class="box">
  <span>sdf223</span>
</div>

</body>
</html>